Benzoxadiazoles and benzothiadiazoles, their preparation and pharmaceutical compositions containing them

ABSTRACT

Compounds of formula I, ##STR1## wherein X is oxygen or sulphur, and R 1  -R 6  are various substituents. 
     The compounds are useful for treating coronary insufficiency, intermittent claudication, cerebrovascular insults, spasms in muscles and hypertension.

This is a continuation of application Ser. No. 173,305 filed July 29, 1980 which in turn is a continuation-in-part of Ser. No. 101,591 filed Dec. 10, 1979, which in turn is a continuation-in-part of Ser. No. 915,858, filed June 15, 1978, all now abandoned.

The present invention relates to benzoxadiazoles and benzothiadiazoles having a 4-dihydropyridine moiety.

The present invention provides in particular compounds of formula I, ##STR2## wherein

R₁ is hydrogen, alkyl(C₁₋₆), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl (C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy (C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆), phenylalkyl(C₇₋₁₀), cycloalkyl(C₃₋₇) or cycloalkylalkyl(C₄₋₈),

R₃ and R₄, independently are CN, COR₇, COOR₇, S(O)_(n) R₇ ##STR3## wherein

n is 0, 1 or 2,

R₇ is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl (C₂₋₆), alkoxyalkyl(C₃₋₆), hydroxyalkoxyalkyl(C₄₋₈), aminoalkyl(C₂₋₆), alkyl(C₁₋₄)aminoalkyl(C₂₋₆), di[alkyl(C₁₋₄)]aminoalkyl, phenyl, phenylalkyl(C₇₋₁₀), a 5- or 6-membered heterocyclic ring containing one heteroatom selected from nitrogen, oxygen or sulphur and may contain additionally 1, 2 or 3 ring nitrogen atoms, or alkyl(C₁₋₄) substituted by a 5- or 6-membered heterocyclic ring containing one heteroatom selected from nitrogen, oxygen or sulphur and may contain additionally 1, 2 or 3 ring nitrogen atoms, is alkylene(C₁₋₆),

R₈ and R₉, independently, are alkyl(C₁₋₆), alkenyl or alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl (C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), hydroxyalkoxyalkyl(C₄₋₈), aminoalkyl(C₂₋₆), alkyl(C₁₋₄)aminoalkyl(C₂₋₆), di[alkyl(C₁₋₄)]aminoalkyl, phenyl, phenylalkyl(C₇₋₁₀), or

R₈ and R₉ together with the nitrogen atom form a 5-, 6-, or 7-membered heterocyclic ring, which may contain a further heteromember selected from oxygen, sulphur and a group ═N--R₁₀, wherein R₁₀ is alkyl (C₁₋₄),

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro, hydroxy, azido, amino, alkyl(C₁₋₄)amino, di[alkyl(C₁₋₄)]amino, alkanoyl(C₁₋₅)amino, carbalkoxy(C₂₋₅), aminocarbonyl, trifluoromethoxy, cyano, sulfamyl, alkyl(C₁₋₄)sulfamyl or di[alkyl (C₁₋₄)]sulfamyl, and

X is oxygen or sulphur. One group of compounds comprises compounds of formula I as defined above, with the proviso that, when

R₁ is hydrogen, alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl (C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl(C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenylring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy(C₁₋₄),

R₂ and R₅, independently, are hydrogen or alkyl(C₁₋₆),

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro or hydroxy, and

X is oxygen or sulphur, then at least one of the substituents R₃ and R₄ is other than COR₇ ^(I), wherein R₇ ^(I) is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), and is other than COOR₇ ^(II), wherein R₇ ^(II) is alkyl(C₁₋₆), alkenyl (C₃₋₆), alkinyl(C₃₋₆),cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆) or hydroxyalkoxyalkyl(C₄₋₈).

In any of the above radicals alkyl of 1 to 6 carbon atoms is preferably of 1 to 4 carbon atoms, especially of 1 to 2 carbon atoms. Any alkyl, alkoxy, alkylthio or alkylsulfonyl radical of 1 to 4 carbon atoms is preferably of 1 to 2 carbon atoms. The hydroxy, alkoxy, hydroxyalkoxy, amino or alkylamino group of the hydroxyalkyl, alkoxyalkyl, hydroxyalkoxyalkyl, aminoalkyl or alkylaminoalkyl moiety in COOR₇ is preferably not attached to the α-carbon atom and is preferably attached to the distal terminal carbon atom. Any hydroxyalkyl, alkoxyalkyl, hydroxyalkoxyalkyl, aminoalkyl or alkylaminoalkyl radical preferably has an ethylene or propylene moiety substituted by hydroxy, alkoxy, hydroxyalkoxy, amino or alkylamino respectively. The alkyl moiety of cycloalkylalkyl is conveniently methyl. Halogen means fluorine, chlorine or bromine and is especially chlorine. Cycloalkyl or the cycloalkyl moiety of cycloalkylalkyl is conveniently cyclopropyl or cyclopentyl or cyclohexyl. The multiple bond of alkenyl, alkinyl or phenylalkenyl in R₁ or COOR₇ is preferably not in the α, βposition. Alkenyl or alkinyl preferably has 3 to 5 carbon atoms. Alkenyl is conveniently allyl or 2-methylallyl. Alkinyl is conveniently propinyl. Phenylalkenyl preferably has the trans-configuration and is for example cinnamyl. When R₁ is optionally substituted phenylalkyl, the phenyl group is preferably unsubstituted. When the phenyl group is di- or tri-substituted, preferably the substituents are the same.

When R₇ is alkyl, this is preferably branched. When R₇ contains a heterocyclic ring this may be for example furyl, thienyl, pyrrolyl, thiazolyl, isothiazolyl, thiadiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, piperidinyl, morpholinyl or triazinyl.

When R₈ and R₉ together with the nitrogen atom to which they are bound, form a heterocyclic ring, this is preferably saturated and may be for example pyrrolidine, piperidine, piperazine, N-alkylpiperazine, morpholine, azepane, diazepane or N-alkyl-diazepane.

R₁ is conveniently hydrogen. R₂ is conveniently identical to R₅. R₂ is conveniently alkyl. R₃ and/or R₄ is conveniently COOR₇ or ##STR4## R₇ is conveniently alkyl, preferably branched or alkoxyalkyl, where the alkoxy moiety is preferably branced. A is conveniently ethylene. R₈ and R₉ are conveniently alkyl or phenylalkyl.

The present invention also provides a process for the production of a compound of formula I as defined above, comprising replacing the moiety --HC═Y in a compound of formula II, ##STR5## wherein R₆ and X are as defined above, and

--HC═Y is

(i) formyl,

(ii) a radical of formula ##STR6## or (iii) a radical of formula ##STR7## wherein Z and Z' are independently oxygen or NR₁, and

R₁ to R₅ are as defined above,

by a moiety of formula III, ##STR8## wherein R₁ to R₅ are as defined above.

The process may be effected in conventional manner for analogous dihydropyridine syntheses, e.g. according to Hantzsch. When the moiety --HC═Y is formyl and when it is desired to produce a compound of formula I, wherein R₂ is identical to R₅ and R₃ is identical to R₄, it is convenient to react a compound of formula II with a compound of formula IV,

    R.sub.5 CO--CH.sub.2 --R.sub.4                             IV

wherein R₄ and R₅ are as defined above, in the presence of a compound of formula V,

    H.sub.2 NR.sub.1                                           V

wherein R₁ is as defined above.

Preferably at least 2 moles of a compound of formula IV per mole of a compound of formula II are present. Alternatively a compound of formula II may be reacted with a compound of formula VI,

    R.sub.5 --C(NH--R.sub.1)═CH--R.sub.4                   VI

wherein R₁, R₄ and R₅ are as defined above.

Preferably at least 2 moles of a compound of formula VI per mole of a compound of formula II are present. Preferably also R₁ is hydrogen.

When the moiety --HC═Y is formyl and preferably when it is desired to produce a compound of formula I wherein R₂ is different to R₅ and/or R₃ is different to R₄, it is also possible to react such a compound of formula II with a compound of formula IV and a compound of formula VII,

    R.sub.2 --C(NH--R.sub.1)═CH--R.sub.3                   VII

wherein R₂, R₁ and R₃ are as defined above.

It will be appreciated that a compound of formula VI may be formed as an intermediate during the reaction of a compound of formula IV and a compound of formula V. A compound of formula II, wherein --HC═Y is a radical (ii) or (iii), may be formed as an intermediate in the above reactions. They may however be produced by different processes.

Alternatively or particularly for the production of a compound of formula I, wherein R₂ is different to R₅ and/or R₃ is different to R₄, it is convenient to react a compound of formula II, wherein the moiety --HC═Y is a radical (ii) with a compound of formula IV or VI, and where appropriate, with a compound of formula V. A compound of formula II, wherein the moiety --HC═Y is a radical (iii) may be an intermediate.

In the above reactions it is possible in certain instances when R₂, R₃, R₄ and R₅ are not identical that more than one isomer of formula I may be formed. If so these may be separated in conventional manner, e.g. by column or thin layer chromatography.

When the starting material is a compound of formula II, wherein --HC═Y is a radical iii), the reaction is a ring cyclisation. When Z and Z' are both oxygen, then an amine of formula V should be present.

However, all the above reactions may be effected under the same conditions.

The reaction may be effected conveniently in solution. A suitable solvent is water, ethanol, dioxane, dimethyl formamide, dimethyl sulphoxide, pyridine or glacial acetic acid. Suitable reaction temperatures may be from 20° to 160° C., preferably from 60° to 120° C.

Insofar as the production of starting materials is not particularly described these compounds are known or may be produced in analoqous manner to known compounds.

The basic compounds for formula I may be converted into acid addition salt forms in conventional manner and vice versa. Suitable acids are e.g. maleic acid, oxalic acid, methanesulphonic acid, hydrochloric acid and hydrobromic acid.

The present invention provides a group of compounds of formula Ia, ##STR9## wherein

R₁ is hydrogen, alkyl of 1 to 6 carbon atoms, alkenyl or alkinyl of 3 to 6 carbon atoms, cycloalkyl of 3 to 7 carbon atoms, cycloalkylalkyl of 4 to 8 carbon atoms, phenylalkyl of 7 to 9 carbon atoms or phenylalkenyl of 9 to 12 carbon atoms, the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy or alkyl or alkoxy of 1 to 4 carbon atoms,

R₂ and R₅, independently, are hydrogen or alkyl of 1 to 6 carbon atoms,

R₃ ^(I) and R₄ ^(I), independently, are alkyl of 1 to 6 carbon atoms, alkenyl or alkinyl of 3 to 6 carbon atoms, cycloalkyl of 3 to 7 carbon atoms, cycloalkylalkyl of 4 to 8 carbon atoms, alkoxy of 1 to 6 carbon atoms, hydroxyalkoxy of 2 to 6 carbon atoms, alkoxyalkoxy of 3 to 6 carbon atoms, hydroxyalkoxyalkoxy of 4 to 8 carbon atoms, alkenyloxy or alkinyloxy of 3 to 6 carbon atoms, cycloalkyloxy of 3 and 7 carbon atoms or cycloalkylalkoxy of 4 to 8 carbon atoms,

R₆ is hydrogen, halogen, alkyl or alkoxy or alkylthio or alkylsulfonyl, each of 1 to 4 carbon atoms, trifluoromethyl, nitro or hydroxy, and

X is oxygen or sulphur.

In any of the above radicals alkyl of 1 to 6 carbon atoms is preferably of 1 to 4 carbon atoms, especially of 1 or 2 carbon atoms. Any alkyl, alkoxy, alkylthio or alkylsulfonyl radical of 1 to 4 carbon atoms is preferably of 1 or 2 carbon atoms. The alkyl moiety of cycloalkylalkyl or cycloalkylalkoxy is conveniently methyl. Halogen means fluorine, chlorine or bromine and is especially chlorine. Cycloalkyl or the cycloalkyl moiety of cycloalkylalkyl or cycloalkylalkoxy is conveniently cyclopropyl or cyclopentyl or cyclohexyl. The multiple bond of alkenyl, alkinyl, alkenyloxy, alkinyloxy or phenylalkenyl is preferably not in the α, βposition. Alkenyl, alkenyloxy, alkinyl or alkinyloxy preferably has 3 to 5 carbon atoms. Alkenyl or the alkenyl moiety of alkenyloxy is conveniently allyl or 2-methylallyl. Alkinyl or the alkinyl moiety of alkinyloxy is conveniently propinyl. Phenylalkenyl preferably has the trans-configuration and is for example cinnamyl. When R₁ is optionally substituted phenyllalkyl, the phenyl group is preferably unsubstituted. When the phenyl group is di- or tri-substituted, preferably the substituents are the same. When R₃ ^(I) and/or R₄ ^(I) is alkoxy, this is preferably ethoxy or methoxy. When R₃ ^(I) and/or R₄ ^(I) is alkoxy-alkoxy or hydroxyalkoxyalkoxy, preferably the carbon chain between the two ether oxygen atoms is of 2 carbon atoms. The hydroxy group of hydroxyalkoxy or of hydroxyalkoxyalkoxy is preferably not attached to the carbon atom attached to an ether oxygen atom. R₁ is preferably hydrogen. R₂ is conveniently identical to R₅. R₂ and/or R₅ is preferably methyl. R₃ ^(I) and/or R₄ ^(I) is preferably alkoxy or alkoxyalkoxy, especially n-butyloxyothoxy. R₆ is conveniently halogen, alkyl or alkoxy, or especially hydrogen. R₆ is conveniently adjacent to the dihydropyridine moiety which in turn is conveniently in the 4-position.

In the following examples all temperatures are in degrees Centrigrade and are uncorrected.

Example 1: 4-(2,1,3-Benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester

3.2 g of 2,1,3-benzoxadiazole-4-aldehyde, 5.7 g of acetoacetic acid ethyl ester, 2.5 ml of concentrated ammonia and 10 ml of ethanol are refluxed for 6 hours. The mixture is subsequently evaporated and the residual oil is chromatographed on silica gel with chloroform/acetic acid ethyl ester (9:1) to yield the title compound. The product is recrystallised from toluene, m.p. 153°-155°.

By using the process described in Example 1, and corresponding starting compounds, e.g. a compound of formula II, wherein --HC═Y is a radical (i) and compounds of formula IV and V, and for Examples 18 and 19 a compound of formula II, wherein --HC═Y is a radical (ii), wherein Z is oxygen and a compound of formula VI, the following compounds of formula Ia may be obtained, wherein y indicates the position of the dihydropyridine moiety:

    __________________________________________________________________________     Example                                                                             R.sub.1                                                                          R.sub.2                                                                           R.sub.3.sup.I                                                                        R.sub.4.sup.I                                                                        R.sub.5                                                                           R.sub.6                                                                             X y m.p.                                         __________________________________________________________________________     2    H CH.sub.3                                                                          OC.sub.2 H.sub.5                                                                     OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          H    S 4 146-148                                      3    H CH.sub.3                                                                          OC(CH.sub.3).sub.3                                                                   OC(CH.sub.3).sub.3                                                                   CH.sub.3                                                                          H    S 4 193-199                                      4    H CH.sub.3                                                                          OCH.sub.3                                                                            OCH.sub.3                                                                            CH.sub.3                                                                          7-Cl O 4 207-211                                      5    H CH.sub.3                                                                          OCH.sub.3                                                                            OCH.sub.3                                                                            CH.sub.3                                                                          H    S 4 215-216                                      6    H CH.sub.3                                                                          OC.sub.2 H.sub.5                                                                     OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          5-OCH.sub.3                                                                         S 4 201-203                                      7    H CH.sub.3                                                                          OC.sub.2 H.sub.5                                                                     OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          7-Cl S 4 135-155                                      8    H CH.sub.3                                                                          OC.sub.2 H.sub.5                                                                     OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          H    S 5 152-153                                      9    H CH.sub.3                                                                          OC.sub.2 H.sub.5                                                                     OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          4-Cl S 5 198-200                                      10   H CH.sub.3                                                                          C(CH.sub.3).sub.3                                                                    C(CH.sub.3).sub.3                                                                    CH.sub.3                                                                          H    S 4                                              11   H CH.sub.3                                                                          CH.sub.3                                                                             CH.sub.3                                                                             CH.sub.3                                                                          7-Cl O 4                                              12   H CH.sub.3                                                                          CH.sub.3                                                                             CH.sub.3                                                                             CH.sub.3                                                                          H    S 4 225-228                                      13   H CH.sub.3                                                                          C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                      CH.sub.3                                                                          5-OCH.sub.3                                                                         S 4                                              14   H CH.sub.3                                                                          C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                      CH.sub.3                                                                          7-Cl S 4                                              15   H CH.sub.3                                                                          C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                      CH.sub.3                                                                          H    S 5                                              16   H CH.sub.3                                                                          C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                      CH.sub.3                                                                          4-Cl S 5                                              17   H CH.sub.3                                                                          CH.sub.3                                                                             CH.sub.3                                                                             CH.sub.3                                                                          H    O 4 218-222                                      18   H CH.sub.3                                                                          CH.sub.3                                                                             OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          H    O 4 186-188                                      19   H CH.sub.3                                                                          CH.sub.3                                                                             OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                          H    S 4 146-148                                      __________________________________________________________________________

Example 20: 4-(2,1,3-Benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxy carbonyl-pyridine-5-carboxylic acid isobutyl ester

3 g of 2,1,3-benzoxadiazole-b 4-aldehyde, 3.2 g of acetoacetic acid isobutyl ester, 2.3 g β-aminocrotonic acid methyl ester and 10 ml of ethanol are stirred under reflux for 3 hours. The mixture is subsequently evaporated and the residue is chromatographed on silica gel with chloroform/acetic acid ethyl ester (8:1) to yield the title compound. The product is recrystallised from diisopropyl ether and methylcyclohexane, m.p. 148°-158°.

By using the process described in Example 1,and corresponding starting compounds, e.g. a compound of formula II, wherein --HC═Y is a radical (i) and compounds of formula IV and V, and for Examples 23, 24 and 27 to 36 a compound fo formula II, wherein --HC═Y is a radical (ii), wherein Z is oxygen and a compound of formula VI, the following compounds of formula Ia, wherein R₂ and R₅ are each methyl and R₆ is hydrogen, may be obtained, wherein y indicates the position of the dihydropyridine moiety:

    __________________________________________________________________________     Comp.                                                                              R.sub.3.sup.I                                                                              R.sub.4.sup.I                                                                            R.sub.1                                                                            y x m.p.                                         __________________________________________________________________________     21  OCH.sub.3   OCH.sub.3 H   4 O 215-221                                      22  OC.sub.2 H.sub.5                                                                           OC.sub.2 H.sub.5                                                                         H   5 O 173-174                                      23  OCH.sub.2 CH(CH.sub.3).sub.2                                                               OC.sub.2 H.sub.5                                                                         H   4 S 85-95                                        24  OCH.sub.2 CH(CH.sub.3).sub.2                                                               OC.sub.2 H.sub.5                                                                         H   4 O   145-146.5                                  25  OC(CH.sub.3).sub.3                                                                         OC(CH.sub.3).sub.3                                                                       H   4 O 207-210                                      26  OCH.sub.2 CH(CH.sub.3).sub.2                                                               OCH.sub.2 CH(CH.sub.3).sub.2                                                             H   4 O 135.5-137                                    27  O(CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                         OC.sub.2 H.sub.5                                                                         H   4 O 126-128                                      28  O(CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                         OC.sub.2 H.sub.5                                                                         H   4 S oil                                          29  O(CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                         OC.sub.2 H.sub.5                                                                         H   5 S 72-78                                        30  OCH(CH.sub.3).sub.2                                                                        OCH.sub.3 H   4 O 168-170                                      31  O(CH.sub.2).sub.2 OCH.sub.3                                                                OCH.sub.3 H   4 O 151- 153                                     32  O(CH.sub.2).sub.2 OCH(CH.sub.3).sub.2                                                      OCH.sub.3 H   4 O 114-120                                      33  O(CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                         OCH.sub.3 H   4 O 140-147                                      34                                                                                  ##STR10##  OCH.sub.3 H   4 O 156-163                                      35  O(CH.sub.2).sub.2 OCH.sub.3                                                                OCH(CH.sub.3).sub.2                                                                      H   4 O 119                                          36  OCH.sub.3   OC.sub.2 H.sub.5                                                                         H   4 O 159                                          37  OC.sub.2 H.sub.5                                                                           OC.sub.2 H.sub.5                                                                         CH.sub.3                                                                           4 O 106                                          38  OC.sub.2 H.sub.5                                                                           OC.sub.2 H.sub.5                                                                         n-C.sub.3 H.sub.7                                                                  4 O  99                                          __________________________________________________________________________

In addition from a compound of formula II, wherein --HC═Y is a radical (ii), wherein Z is oxygen and a compound for formula VI there may be made the following compounds of formula I, wherein y indicates the position of the dihydropyridine moiety:

    __________________________________________________________________________     Ex.                                                                               R.sub.1                                                                          R.sub.2                                                                           R.sub.3      R.sub.4    R.sub.5                                                                           R.sub.6                                                                          X y m.p.                                  __________________________________________________________________________     39 H CH.sub.3                                                                          CN           COOi-Bu    CH.sub.3                                                                          H O 4 123-124.5                             40 H CH.sub.3                                                                          COOC.sub.2 H.sub.5                                                                          SO.sub.2 CH.sub.3                                                                         CH.sub.3                                                                          H O 4 204-205                               41 H CH.sub.3                                                                          CN           COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H O 4 167-177                               42 H CH.sub.3                                                                          CN           COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H S 4 187-190                               43 H CH.sub.3                                                                          CN           COOCH.sub.2 CH(CH.sub.3).sub.2                                                            CH.sub.3                                                                          H S 4 166-171                               44 H CH.sub.3                                                                          COOCH.sub.3  COC.sub.6 H.sub.5                                                                         CH.sub.3                                                                          H O 4 192-201                               45 H CH.sub.3                                                                           ##STR11##   COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H O 4 180-184**                             46 H CH.sub.3                                                                           ##STR12##   COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H S 4 173-175**                             47 H CH.sub.3                                                                          COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                       COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                     CH.sub.3                                                                          H O 4 188-191*                                                                       fumarate                              48 H CH.sub.3                                                                          COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                       COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                     CH.sub.3                                                                          H S 4 156-159                                                                        fumarate                              49 H CH.sub.3                                                                          COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                       COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H O 4                                       50 H CH.sub.3                                                                          COO(CH.sub.2).sub.2 N(CH.sub.3).sub.2                                                       COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H S 4 166-176                                                                        hydrogen-                                                                      fumarate                              51 H CH.sub.3                                                                           ##STR13##   COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H S 5 oil                                   52 H CH.sub.3                                                                           ##STR14##   COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H O 5 oil                                   53 H CH.sub.3                                                                           ##STR15##   COOCH.sub.3                                                                               CH.sub.3                                                                          H O 4 182-195**                             54 H Δ                                                                           COOC.sub.2 H.sub.5                                                                          COOC.sub.2 H.sub.5                                                                        CH.sub.3                                                                          H O 4  97-99                                55 H Δ                                                                           COOCH.sub.3  COOCH.sub.3                                                                               CH.sub.3                                                                          H O 4 160-163                               56 H Δ                                                                           COOCH.sub.3  COOCH.sub.3                                                                               Δ                                                                           H O 4 118-120                               57 H Δ                                                                           COOC.sub.2 H.sub.5                                                                          COOC.sub.2 H.sub.5                                                                        Δ                                                                           H O 4 110-112                               58 H CH.sub.3                                                                          COO(CH.sub.2).sub.2C.sub.6 H.sub.5                                                          COOCH.sub.3                                                                               CH.sub.3                                                                          H O 4 156                                   59 H CH.sub.3                                                                          COOCH.sub.3  COOCH.sub.2 C.sub.6 H.sub.5                                                               CH.sub.3                                                                          H O 4 131-136                               __________________________________________________________________________      * decomposition                                                                ** hydrochloride                                                         

In addition from a compound of formula II, wherein --HC═Y is a radical (ii), wherein Z is oxygen and a compound of formula VI there may be made the following compounds of formula Ia wherein X=S and the 1,4-dihydropyridine moiety is in the 5-position and R₁ to R₆ are respectively:

    __________________________________________________________________________     (a)       CH.sub.3 ; H; nC.sub.6 H.sub.13 ; nC.sub.6 H.sub.13 ; H;                       4-C.sub.2 H.sub.5 ; or                                               (b)       nC.sub.6 H.sub.13 ; nC.sub.6 H.sub.13 ; C.sub.2 H.sub.5.CHCH.CH.               sub.2 ; C.sub.2 H.sub.5.CHCH.CH.sub.2 ; nC.sub.6 H.sub.13 ;                    6-C.sub.2 H.sub.5 S; or                                                (c)                                                                                     ##STR16##                                                             (d)                                                                                     ##STR17##                                                             (e)                                                                                     ##STR18##                                                             (f)                                                                                     ##STR19##                                                             (g)                                                                                     ##STR20##                                                              (h)                                                                                    ##STR21##                                                             (i)                                                                                     ##STR22##                                                             (j)                                                                                     ##STR23##                                                             (k)                                                                                     ##STR24##                                                             (l)     nC.sub.6 H.sub.13 ; nC.sub.6 H.sub.13 ; CHCCH.sub.2 ;                          CHCCH.sub.2 ; nC.sub.6 H.sub.13 ; 6-C.sub.2 H.sub.5 S; or              (m)                                                                                     ##STR25##                                                             (n)                                                                                     ##STR26##                                                             (o)                                                                                     ##STR27##                                                           __________________________________________________________________________       R.sub.1 R.sub.2                                                                               R.sub.3 R.sub.4    R.sub.5                                                                               R.sub. 6                                                                            y X                            __________________________________________________________________________       (p)                                                                            C.sub.4 H.sub.8 CCH                                                                    CH.sub.3                                                                               ##STR28##                                                                             COOCH.sub.2 CCH                                                                           CH.sub.3                                                                              7-OCF.sub.3                                                                         5 S                              (q)                                                                            CCC.sub.2 H.sub.5                                                                      H                                                                                      ##STR29##                                                                              ##STR30## C.sub.2 H.sub.5                                                                       6-CN 4 S                              (r)                                                                             ##STR31##                                                                              ##STR32##                                                                            SOC.sub.2 H.sub.4 OC.sub.2 H.sub.5                                                     COCH.sub.2CHCH.sub.2                                                                       ##STR33##                                                                            7-nC.sub.4 H.sub.9                                                                  4 O                              (s)                                                                             ##STR34##                                                                             C.sub.2 H.sub.5                                                                       CN      CO(CH.sub.2).sub.2 N(C.sub.3 H.sub.7).sub.2                                               C.sub.2 H.sub.5                                                                       6-Br 5 S                              (t)                                                                             ##STR35##                                                                             C.sub.2 H.sub.5                                                                       CN      COOCH.sub.2CCH                                                                            CH.sub.3                                                                              6-Br 5 S                            __________________________________________________________________________

By using the process described in Example 1, and corresponding starting compounds, e.g. a compound of formula II, wherein --HC═Y is a radical (i) and compounds of formula IV and V, and for Examples 61, 62 and 65 to 74 a compound of formula II, wherein --HC═Y is a radical (ii), wherein Z is oxygen and a compound of formula VI, the following compounds of formula I, wherein R₂ and R₅ are each methyl and R₆ is hydrogen, may be obtained, wherein y indicates the position of the dihydropyridine moiety and R₃ and R₄ are COR₇ ^(I) and COR₇ ^(II) respectively:

    ______________________________________                                         Comp. R.sub.7.sup.I  R.sub.7.sup.II                                                                             R.sub.1                                                                              y   X                                   ______________________________________                                         60    C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                            H     5   O                                   61    CH.sub.2 CH(CH.sub.3).sub.2                                                                   C.sub.2 H.sub.5                                                                            H     4   S                                   62    CH.sub.2 CH(CH.sub.3).sub.2                                                                   C.sub.2 H.sub.5                                                                            H     4   O                                   63    C(CH.sub.3).sub.3                                                                             C(CH.sub.3).sub.3                                                                          H     4   O                                   64    CH.sub.2 CH(CH.sub.3).sub.2                                                                   CH.sub.2 CH(CH.sub.3).sub.2                                                                H     4   O                                   65    (CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                             C.sub.2 H.sub.5                                                                            H     4   O                                   66    (CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                             C.sub.2 H.sub.5                                                                            H     4   S                                   67    (CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                             C.sub.2 H.sub.5                                                                            H     5   S                                   68    CH(CH.sub.3).sub.2                                                                            CH.sub.3    H     4   O                                   69    (CH.sub.2).sub.2 OCH.sub.3                                                                    CH.sub.3    H     4   O                                   70    (CH.sub.2).sub.2 OCH(CH.sub.3).sub.2                                                          CH.sub.3    H     4   O                                   71    (CH.sub.2).sub.2 OC.sub.2 H.sub.5                                                             CH.sub.3    H     4   O                                   72                                                                                    ##STR36##     CH.sub.3    H     4   O                                   73    (CH.sub.2).sub.2 OCH.sub.3                                                                    CH(CH.sub.3).sub.2                                                                         H     4   O                                   74    CH.sub.3       C.sub.2 H.sub.5                                                                            H     4   O                                   75    C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                            CH.sub.3                                                                             4   O                                   76    C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                            n-C.sub.3 H.sub.7                                                                    4   O                                   ______________________________________                                    

The compounds of formula I exhibit pharmacological activity. In particular, they lead to a dilation of the coronary vessels as demonstrated by the results of tests measuring the blood flow to the myocardium of an anaesthetised cat by means of the microsphere method (Rudolph A. M. and Heymann M. S.: Circulation Research 21, 163, 1967) upon administration of from 30to 50 μg/kg i.v. or of from 50 to 150 μg/kg i.d. of the active substance.

The compounds of formula I also possess a favourable effect against angina pectoris, as shown by the increase of the coronary flow of an anesthetised cat upon administration of the active substance.

The compounds of formula I are useful in the treatment of coronary insufficiency. For the abovementioned use the dosage will, of course, vary depending on the compound employed, mode of administration and therapy desired. However, in general satisfactory results are obtained with a daily dosage of 0.01 to 10 mg/kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form, For the larger mammal, the total daily dosage is in the range from about 5 to 100 mg, and dosage forms suitable for oral administration comprise from about 1.25 mg to about 50 mg of the compounds admixed with a solid or a liquid pharmaceutical carrier or diluent.

The compounds of formula I increase the blood flow to limbs, e.g. leg musculature, as can be shown by means of the microsphere method on the anaesthetised cat upon administration of from 30 to 50 μg/kg i.v. or from 50 to 150 μg/kg i.d. of the compounds.

The compounds of formula I are therefore useful for treatment of intermittent claudication and other peripheral disturbances of blood flow to limb muscles. For the above-mentioned use the dosage will, of course, vary depending on the compound employed, mode of administration and therapy desired. However, in general satisfactory results are obtained with a daily dosage of 0.01 to 10 mg/kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form. For the larger mammal, the total daily dosage is in the range from about 5 to 100 mg, and dosage forms suitable for oral administration comprise from about 1.25 mg to about 50 mg of the compounds admixed with a solid or a liquid pharmaceutical carrier or diluent.

The compounds of formula I increase cerebral blood flow, as can be shown by means of the microsphere method on the anesthetised cat upon administration of from 30 to 50 μg/kg i.v. or from 50 to 150 μg/kg i.d. of the compounds.

The compounds of formula I are therefore useful in the treatment of cerebrovascular insults (accidents). For the above-mentioned use the dosage will, of course, vary depending on the compound employed, mode of administration and therapy desired. However, in general satisfactory results are obtained with a daily dosage of 0.01 to 10 mg/kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form. For the larger mammal, the total daily dosage is in the range from about 5 to 100 mg, and dosage forms suitable for oral administration comprise from about 1.25 mg to about 50 mg of the compounds admixed with a solid or a liquid pharmaceutical carrier or diluent.

The compounds of formula I possess calciumantagonistic activity, as indicated in standard tests, for example by an inhibition of a calcium induced contraction of isolated dog coronary arteries suspended in a depolarizing solution at concentration of 10⁻¹⁰ to 10⁻⁸ M of the compounds according to the principles of Godfraind and Kaba, Brit. J. Pharm. 36, 549-560, 1969. The compounds are therefore useful as spasmolytic agents, for the treatment of spasms in muscles. For the above-mentioned use the dosage will of course, vary depending on the compound employed, mode of administration and therapy desired. However, in general satisfactory results are obtained with a daily dosage of 0.01 to 10 mg/kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form. For the larger mammal, the total daily dosage is in the range from about 5 to 100 mg, and dosage forms suitable for oral administration comprise from about 1.25 mg to about 50 mg of the compounds admixed with a solid or a liquid pharmaceutical carrier or diluent.

Additionally, the compounds of formula I exhibit antihypertensive activity, as indicated by a blood pressure lowering activity in standard tests.

For example, the compounds exhibit a blood pressure lowering effect in the Grollman rat test [see A. Grollman, Proc. Soc. Expt. Biol. and Med. 57, 104 (1944)] on s.c. administration of from 0.1 to 10 mg/kg animal body weight of the compounds.

The compounds are therefore useful as anti-hypertensive agents. For this use the dosage will, of course, vary depending on the compound employed, mode of administration and therapy desired. However, in general, satisfactory results are obtained with a daily dosage of from 0.5 to 50 mg/kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form. For the larger mammal, the total daily dosage is in the range form about 5 to about 1000 mg, e.g. 30 to 1000 mg, and dosage forms suitable for oral administration comprise from about 1.25 mg to about 500 mg of the compounds admixed with a solid or liquid pharmaceutical carrier or diluent.

A compound of formula I may be administered in free base form. Alternatively any sufficiently basic compound of formula I, e.g. those compounds wherein R₃ or R₄ contain an amino moiety, may be administered in pharmaceutically acceptable acid addition salt form. Such acid addition salt forms exhibit the same order of activity as the free base forms. The present invention also provides a pharmaceutical composition comprising a compound of formula I in association with a pharmaceutical carrier or diluent. Such compositions may be prepared by conventional techniques to be in conventional forms, for example capsules or tablets.

The compounds of Examples 1, 20, 24, 30-38, 45, 53 and 59 are particularly interesting. The coronary insufficiency, the intermittent claudication, the cerebrovascular insufficiency and the spasmolytic activities are the preferred utilities for compounds of formula I.

In a group of compounds of formula Ia R₁ is hydrogen, alkyl, alkenyl, cycloalkyl of 3 to 6 carbon atoms, phenylalkyl, or phenylalkenyl; the phenyl ring being unsubstituted or substituted by one, two or three substituents chosen from one or two halogen radicals, one or two alkyl groups of 1 to 4 carbon atoms, one to three alkoxy groups of 1 to 4 carbon atoms; R₃ ^(I) and R₄ ^(I), independently, are alkyl, alkenyl, cycloalkyl of 3 to 6 carbon atoms, alkoxy, hydroxyalkoxy of 2 to 6 carbon atoms, alkoxyalkoxy of 3 to 6 carbon atoms, hydroxyalkoxyalkoxy of 4 to 8 carbon atoms, alkenyloxy, or cycloalkyloxy of 3 to 6 carbon atoms, and R₆ is other than alkylsulfonyl.

Conveniently R₁ is hydrogen, R₂ and R₅ are each alkyl, especially methyl, R₃ ^(I) and R₄ ^(I) are each alkoxy, especially ethoxy, R₆ is hydrogen or halogen, especially chlorine, especially in the 4 position, the dihydropyridine moiety is in the 4 or 5 position, and X is S.

Alternatively conveniently R₁ is hydrogen, R₂ and R₅ are each alkyl, especially methyl, R₃ ^(I) and R₄ ^(I) are alkyl or alkoxy, especially methyl, ethyl, tert. butyl, methoxy, ethoxy or tert. butyloxy, R₆ is hydrogen or halogen, especially chlorine, or alkoxy, especially methoxy, the dihydropyridine moiety is in the 4 or 5 position and R₆ is in the 4, 5 or 7 position.

In one group of compounds of formula I R₁ is hydrogen, alkyl(C₁₋₆), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl(C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy (C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆) or phenylalkyl(C₇₋₁₀),

R₃ and R₄, independently are CN, COR₇, COOR₇ or S(O)_(n) R₇, wherein

n is 0, 1 or 2,

R₇ is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), hydroxyalkoxyalkyl(C₄₋₈), aminoalkyl(C₂₋₆), alkyl(C₁₋₄)aminoalkyl(C₂₋₆), phenyl, phenylalkyl(C₇₋₁₀), a 5- or 6-membered heterocyclic ring containing one heteroatom selected from nitrogen, oxygen or sulphur, or alkyl(C₁₋₄) substituted by a 5- or 6-membered heterocyclic ring containing one heteroatom selected from nitrogen, oxygen or sulphur,

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro, hydroxy, azido, amino, alkyl(C₁₋₄)amino, alkanoyl(C₁₋₅)amino, carbalkoxy(C₂₋₄), aminocarbonyl, trifluoromethoxy, cyano, sulfamyl, alkyl(C₁₋₄)sulfamyl or di[alkyl(C₁₋₄)]sulfamyl, and

X is oxygen or sulphur, with the proviso that when R₁ is hydrogen, alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl(C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenylring being unsubstituted or mono-, di- or tri-substituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy(C₁₋₄),

R₂ and R₅, independently, are hydrogen or alkyl(C₁₋₄),

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro or hydroxy, and

X is oxygen or sulphur, then at least one of the substituents R₃ and R₄ is other than COR₇ ^(I), wherein R₇ ^(I) is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), and is other than COOR₇ ^(II), wherein R₇ ^(II) is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆) or hydroxyalkoxyalkyl(C₄₋₈).

In another group of compounds of formula I

R₁ is hydrogen, alkyl(C₁₋₆), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl(C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy(C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆) or phenylalkyl(C₇₋₁₀),

R₃ is ##STR37## and

R₄ is CN, COR₇, COOR₇, S(O)_(n) R₇ or ##STR38## wherein n is 2,

R₇ is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), hydroxyalkoxyalkyl(C₄₋₈), aminoalkyl(C₂₋₆), alkyl(C₁₋₄)aminoalkyl(C₂₋₆), phenyl or phenylalkyl(C₇₋₁₀),

A is alkylene(C₁₋₆),

R₈ and R₉, independently, are alkyl(C₁₋₆), alkenyl or alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), hydroxyalkoxyalkyl(C₄₋₈), aminoalkyl(C₂₋₆), alkyl(C₁₋₄)aminoalkyl(C₂₋₆), phenyl, phenylalkyl(C₇₋₁₀),

or

R₈ and R₉ together with the nitrogen atom form a 5-, 6- or 7-membered heterocyclic ring, which may contain a further heteromember selected from oxygen, sulphur and a group ═N--R₁₀, wherein R₁₀ is alkyl(C₁₋₄), and

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro, hydroxy, azido, amino, alkyl(C₁₋₄)-amino, alkanoyl(C₁₋₅)amino, carbalkoxy(C₂₋₅), aminocarbonyl, trifluoromethoxy, cyano or sulfamyl, and

X is oxygen or sulphur.

In another group of compounds of formula I

R₁ is hydrogen, alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl(C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy(C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆), phenylalkyl(C₇₋₁₀), cycloalkyl(C₃₋₇) or cycloalkylalkyl(C₄₋₈),

R₃ and R₄, independently, are COR₇ ^(I) or COOR₇ ^(II), wherein R₇ ^(I) is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), and R₇ ^(II) is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆) or hydroxyalkoxyalkyl(C₄₋₈),

R₆ is hydrogen, halogen, alkyl(C₁₋₄), alkoxy(C₁₋₄), alkylthio(C₁₋₄), alkylsulfonyl(C₁₋₄), trifluoromethyl, nitro or hydroxy, and

X is oxygen or sulphur, with the proviso, that at least one of the substituents R₂ and R₅ is phenylalkyl(C₇₋₁₀), cycloalkyl(C₃₋₇) or cycloalkylalkyl(C₄₋₈).

A group of compounds are compounds of formula I, wherein

R₁ is alkyl(C₁₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇),

R₂ and R₅, independently, are hydrogen or alkyl(C₁₋₆),

R₃ and R₄, independently, are COOR₇, wherein R₇ is other than phenylalkyl.

These compounds show surprisingly beneficial pharmacological activity than is expected for compounds of this type, e.g. long lasting coronary sufficiency activity in the tests mentioned above and good tolerability.

In another group of formula I

R₁ is alkyl(C₁₋₆), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl (C₇₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy(C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆), phenylalkyl(C₇₋₁₀), cycloalkyl(C₃₋₇) or cycloalkylalkyl(C₄₋₈),

R₃ and R₄, independently are CN, COR₇, COOR₇, S(O)_(n) R₇ or ##STR39## subject to the proviso as defined above, provided that R₃ and R₄ are not both COOR₇, wherein R₇ is alkyl(C₁₋₆).

In another group of compounds of formula I

R₁ is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇),

R₂ and R₅, independently, are hydrogen or alkyl(C₁₋₆),

R₃ and R₄, independently, are CN, COR₇, COOR₇, S(O)_(n) R₇ or ##STR40## wherein n, R₇, A, R₈ and R₉ and subject to the proviso as defined above and provided that R₃ and R₄ are not both COOR₇, wherein R₇ is alkyl(C₁₋₆).

In a sub-group R₆ is alkylsulfonyl(C₁₋₄), hydroxy, azido, amino, alkyl(C₁₋₄)amino, di[alkyl(C₁₋₄)] amino, alkanoyl(C₁₋₅)amino, aminocarbonyl, tri-fluoromethoxy, sulfamyl, alkyl(C₁₋₄)sulfamyl or di[alkyl(C₁₋₄)]sulfamyl.

In another group of compounds of formula I

R₁ is hydrogen, alkyl(C₁₋₆), hydroxyalkyl(C₂₋₆), alkoxyalkyl(C₃₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆), cycloalkyl(C₃₋₇), cycloalkylalkyl(C₄₋₈), phenylalkyl (C₈₋₉) or phenylalkenyl(C₉₋₁₂), the phenyl ring being unsubstituted or mono-, di- or trisubstituted independently by halogen, hydroxy, alkyl(C₁₋₄) or alkoxy (C₁₋₄),

R₂ and R₅, independently, are hydrogen, alkyl(C₁₋₆), phenylalkyl(C₇₋₁₀), cycloalkyl(C₃₋₇) or cycloalkylalkyl(C₄₋₈),

R₃ and R₄, independently are CN, COR₇, COOR₇, S(O)_(n) R₇ or ##STR41## wherein n, R₇, A, R₈ and R₉ and subject to the proviso as defined above, provided that R₃ and R₄ are not independently COR₇, wherein R₇ is alkyl(C₁₋₆), alkenyl(C₃₋₆), alkinyl(C₃₋₆) or COOR₇, wherein R₇ is other than phenyl or phenylalkyl as defined above.

In a first group of compounds R₁ is hydrogen.

In a second group of compounds R₁ is alkyl.

In a third group of compounds R₁ is hydroxyalkyl.

In a fourth group of compounds R₁ is alkoxyalkyl.

In a fifth group of compounds R₁ is alkenyl.

In a sixth group of compounds R₁ is alkinyl.

In a seventh group of compounds R₁ is cycloalkyl.

In an eighth group of compounds R₁ is cycloalkylalkyl.

In a ninth group of compounds R₁ is phenylalkyl.

In a tenth group of compounds R₁ is phenylalkenyl.

In an eleventh group of compounds R₂ is alkyl.

In a twelfth group of compounds R₂ is hydrogen.

In a thirteenth group of compounds R₂ is phenylalkyl.

In a fourteenth group of compounds R₂ is cycloalkyl.

In a fifteenth group of compounds R₂ is cycloalkylalkyl.

In a sixteenth group of compounds R₅ is alkyl.

In a seventeenth group of compounds R₅ is hydrogen.

In an eighteenth group of compounds R₅ is phenylalkyl.

In a nineteenth group of compounds R₅ is cycloalkyl.

In a twentieth group of compounds R₅ is cycloalkylalkyl.

In a twentyfirst group of compounds R₅ is identical to R₂.

In a twentysecond group of compounds R₅ is a different radical type from R₂.

In a twentythird group of compounds R₃ is identical to R₄.

In a twentyfourth group of compounds R₃ is a different radical type from R₄.

In a twentyfifth group of compounds R₃ ^(I) is a different radical type from R₄ ^(I).

In a twentysixth group of compounds R₃ independently is COR₇.

In a twentyseventh group of compounds R₃ independently is COOR₇.

In a twentyeighth group of compounds R₃ independently is SR₇.

In a twentyninth group of compounds R₃ independently is SOR₇.

In a thirtieth group of compounds R₃ independently is SO₂ R₇.

In a thirtyfirst group of compounds R₃ independently is ##STR42##

In a thirtysecond group of compounds R₄ is COR₇.

In a thirtythird group of compounds R₄ is COOR₇.

In a thirtyfourth group of compounds R₄ is SR₇.

In a thirtyfifth group of compounds R₄ is SOR₇.

In a thirtysixth group of compounds R₄ is SO₂ R₇.

In a thirtyseventh group of compounds R₄ is COO-A-NR₈ R₄.

In a thirtyeighth group of compounds R₇ is alkyl.

In a thirtyninth group of compounds R₇ is alkenyl.

In a fourtieth group of compounds R₇ is alkinyl.

In a fourtyfirst group of compounds R₇ is cycloalkyl.

In a fourtysecond group of compounds R₇ is cycloalkyl.

In a fourtythird group of compounds R₇ is cycloalkylalkyl.

In a fourtyfourth group of compounds R₇ is hydroxyalkyl.

In a fourtyfifth group of compounds R₇ is alkoxyalkyl.

In a fourtysixth group of compounds R₇ is hydroxyalkoxyalkyl.

In a fourtyseventh group of compounds R₇ is aminoalkyl.

In a fourtyeighth group of compounds R₇ is alkylaminoalkyl.

In a fourtyninth group of compounds R₇ is di[alkyl]aminoalkyl.

In a fiftieth group of compounds R₇ is phenyl.

In a fiftyfirst group of compounds R₇ is phenylalkyl.

In a fiftysecond group of compounds R₇ is a heterocyclic ring.

In a fiftythird group of compounds R₇ is an alkyl group substituted by a heterocyclic ring.

In a fiftyfourth group of compounds A is ethylene.

In a fiftyfifth group of compounds X is oxygen.

In a fiftysixth group of compounds X is sulphur.

Any of the above groups may be combined to produce e.g. groups wherein the dihydropyridine substituents in positions 3 and 5, and/or 2 and 6 are identical, different or of a different type (e.g. are grouped in separate groups above). 

What we claim is:
 1. A compound having the formula ##STR43## wherein R₁ ' is hydrogen or C₁₋₆ alkyl;R₂ ' and R₅ ', independently, are hydrogen or C₁₋₆ alkyl; R₃ ' and R₄ ', independently, are COOR₇ ' or ##STR44## each R₇ ', independently, is C₁₋₆ alkyl, C₃₋₇ -cycloalkyl, C₇₋₁₀ phenylalkyl or C₃₋₆ alkoxyalkyl;A is C₁₋₆ alkylene; eachR₈ ' and R₉ ', independently, is C₁₋₆ alkyl or C₇₋₁₀ phenylalkyl; and X is oxygen or sulphur,or a pharmaceutically acceptable acid addition salt of a basic compound of the above formula.
 2. A compound of claim 1 wherein R₁ ' is hydrogen.
 3. A compound according to claim 1 wherein R₁ ' is hydrogen, R₂ ' and R₅ ' are C₁₋₆ alkyl, R₃ ' and R₄ ' are COOR₇ ' where R₇ ' is C₁₋₆ alkyl and X is sulphur.
 4. A compound according to claim 3 where R₂ ' and R₅ ' are methyl and R₇ ' is methyl, ethyl or t-butyl.
 5. A compound according to claim 4 where R₇ ' is ethyl.
 6. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester.
 7. The compound of claim 1 which is 4-(2,1,3-benzothiadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid dimethyl ester.
 8. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxycarbonylpyridine-5-carboxylic acid isobutyl ester.
 9. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-isopropyloxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 10. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-isopropyloxyethoxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 11. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-ethoxyethoxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 12. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-cyclopentyloxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 13. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-N-benzyl-N-methylamino ethoxycarbonyl-pyridine-5-carboxylic acid ethyl ester, or a pharmaceutically acceptable acid addition salt thereof.
 14. The compound of claim 1 which is 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxycarbonyl-pyridine-5-carboxylic acid benzyl ester.
 15. The compound of claim 1 which is 4-(2,1,3-benzothiadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-isobutyloxycarbonyl-pyridine-5-carboxylic acid ethyl ester.
 16. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-isobutyloxycarbonyl-pyridine-5-carboxylic acid ethyl ester.
 17. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-ethoxyethoxycarbonyl-pyridine-5-carboxylic acid ethyl ester.
 18. The compound of claim 1 which is 4-(2,1,3-benzothiadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-ethoxyethoxycarbonyl-pyridine-5-carboxylic acid ethyl ester.
 19. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxyethoxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 20. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxyethoxycarbonyl-pyridine-5-carboxylic acid isopropyl ester.
 21. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-methoxycarbonyl-pyridine-5-carboxylic acid ethyl ester.
 22. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-1-propyl-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester.
 23. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-N-benzyl-N-methylamino ethoxycarbonyl-pyridine-5-carboxylic acid methyl ester, or a pharmaceutically acceptable acid addition salt thereof.
 24. A pharmaceutical composition useful in treating coronary insufficiency comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 25. A pharmaceutical composition useful in treating intermittent claudication comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 26. A pharmaceutical composition useful in treating cerebrovascular accidents comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 27. A pharmaceutical composition useful in treating muscular spasms comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 28. A pharmaceutical composition useful in treating hypertension comprising a pharmaceutically acceptable carrier or diluent and a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 29. The compound of claim 1 which is 4-(2,1,3-benzoxadiazole-4-yl)-2,6-dimethyl-1,4-dihydro-3-phenethyloxycarbonyl-pyridine-5-carboxylic acid methyl ester.
 30. A method of treating coronary insufficiency comprising administering to an animal in need of such treatment a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 31. A method of treating intermittent claudication comprising administering to an animal in need of such treatment a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 32. A method of treating cerebrovascular accidents comprising administering to an animal in need of such treatment a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 33. A method of treating muscular spasms comprising administering to an animal in need of such treatment a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof.
 34. A method of treating hypertension comprising administering to an animal in need of such treatment a therapeutically effective amount of a compound of claim 1, or a pharmaceutically acceptable acid addition salt thereof. 